1. Field of the Invention
The invention relates to concentrates of ursolic acid and oleanoic acid and their use in foods or as food supplements.
2. Description of Related Art
Ursolic acid and oleanoic acid are well known compounds that can be isolated from a number of fruit skins. A typical example of fruit skins that can be applied are apple skins, but more sources are disclosed in e.g. col.2, 1.16-20 of U.S. Pat. No. 5,948,460. In literature (cf e.g JP 09/020674 or SU 827066 or de Sousa Menezes in Anais da Bras de Cincias, Acad Brasileira de Cincias, Rio de Jan vol 70, 1998, p.761 or Bock c.s in Die Nahrung vol 10, 1966, p.409 or Croteau in Phytochem vol 8, 1969 p.219) a standard procedure for isolating ursolic acid and/or oleanoic acid from fruit skins is to perform an extraction of the skins with an organic solvent such as acetone or ethanol. However the results of the prior art techniques were found to be unsatisfactory for a number of reasons. It was found that the products obtained had a severe off taste which prevented their use in food products. Further the compounds could only be obtained in low yields, which was probably due to the presence of high amounts of unidentified organic compounds in the fruit skins, possibly being monomolecular and higher molecular sugar residues, which makes the working-up of the extraction product very difficult. Further it was found that the purity of the products obtained was far below what is considered as acceptable for use in foods while the products also had an undesired greenish colour which made them less acceptable for use in food products that should have a light or bland colour.
We therefore studied whether we could find ways to overcome above disadvantages and to come to concentrates of ursolic acid and oleanoic acid that do not display these disadvantages.
This study resulted in the finding of novel concentrates that comprise relatively large amounts of ursolic acid and oleanoic acid or their food acceptable salts such as their alkali or alkali earth metal salts and that could be used in foods directly without the disadvantages of the known concentrates.Therefore our invention concerns in the first instance a concentrate comprising ursolic acid and oleanoic acid or their food acceptable dsalts in substantial amounts, wherein the concentrate comprises:
(i) ursolic acid and oleanoic acid or their food acceptable salts in an total amount for the two of more than 22 wt % preferably 30 to 65 wt %
(ii) sugar residues in an amount of less than 40 wt %, preferably less than 25 wt %, in particular in an amount of 1 to 10 wt %
(iii) while ursolic acid and oleanoic acid or their salts are present in a weight ratio of more than 3.6, preferably 4.0 to 6.0
(iv) the balance being other materials, including glycerides and/or triterpenes other than ursolic acid and oleanoic acid.
The sugar residues can comprise mono-molecular sugars such as glucose and fructose but also di-molecular carbohydrates such as sucrose and even oligomers of carbohydrates.
Preferred products are those products wherein the other materials (iv) are present in amounts of 15 to 65 wt %, more preferably 25 to 50 wt % These other materials comprise glycerides and other triterpenes, in particular the other materials comprise 1 to 40% glycerides and for the rest other triterpenes which other terpenes comprise maslinic acid and/or pomolic acid and/or pirolonic acid
Food products containing the novel concentrates are also part of the invention and thus the invention also covers food products comprising an effective amount of the concentrate as described above so that the food product can deliver by a normal daily consumption of the food product 10 to 100% of the recommended daily amount of ursolic acid and oleanoic acid. Recommended daily amounts can range from 10 mg to 4 gram per kilogram human body weight depending on the type of deficiency that is intended to be treated with the use of the food product cq health component. The effective amount being that amount that displays a noticeable effect of the consumption of the health component.
The novel concentrates can also be used in the form of food supplements and therefore our invention also concerns food supplements comprising the concentrate according to the invention in encapsulated form. The concentrates can be encapsulated in food grade or food acceptable materials, in particular the encapsulating material used herefore is selected from the group consisting of sugars, starches, modified starches, hydrocolloids, gums and gelatin
In order to enable an economic and feasable route to isolate an useful concentrate of ursolic acid and oleanoic acid from natural waste materials we developed a new process. This process led to higher yields of the desired active components (ursolic acid and oleanoic acid present in this waste material) while simultaneously these active components were obtained in purer form than achievable so far. Thus according to another embodiment of our invention our invention also concerns a method for producing a concentrate with the composition according to the invention by:
(i) selecting a natural material comprising ursolic acid and oleanoic acid in sufficient amounts
(ii) drying to a water level of less than 10 wt % of either
a) the natural material of step (i) or
b) milled or ground wet material of step (iii a)
(iii) milling or grinding of either
a) the wet natural material of step (i) or
b) the dried natural material of step (ii a),
(iv) extracting of either
a) the milled or ground material resulting from step (iii b) or
b) the milled or ground material from step (ii a)
with an organic solvent, preferably being acetone, ethyl acetate or ethanol and collecting an extract of the final concentrate in the solvent
(v) removing the solvent from the extract obtained after step (iv a) or step (iv b).
In those instances wherein the food acceptable salts are desired the above extract can be treated with a base and the salts can be isolated.
Although above process already resulted in better products and higher yields we found that these products and yields could be further improved if step (ii) or step (iii) is either preceeded or followed by a wash with an aqueous solution, followed in case a wet product is obtained by a drying, which aqueous solution preferably is applied in a weight ratio between aqueous solution and natural material of more than 2 to 1, preferably 5:1 to 30:1
Further improvements were obtained if the aqueous solution is a solution of a base and preferably has a pH of 8 to 12 or if the aqueous solution is an acidic solution, preferably with a pH=0 to 2. The best results were obtained by performing a process wherein the milling is preceeded or followed by a treatment with acid and with base (or the other way round) using an intermediate wash until about neutral. So a combined base/acid treatment is used, however the order of these treatments was found to be irrelevant.
Although many different sources of starting materials can be used in our process we found that the best results were obtained when using a cheap and easily available starting material in the form of apple skins.
We further noticed that the particle size of the products obtained after our milling or grinding step(s) also had an impact on the efficiency of our process. It was found that the best results were obtained if the milling or grinding is performed until particles are obtained with a particle size of less than 20 mm, preferably 2 to 20 mm.
Another important product parameter is the temperature during the aequous wash. It was found that the best results were obtained when using a temperature of at least 35xc2x0 C., in particular at least 70xc2x0 C.
The concentrates that we obtained can be used in food products for many different purposes. They e.g. can be applied in order to provide the food product with the health function known for ursolic acid resp. oleanoic acid. However we also found that these components had an impact on the crystallisation behaviour of the fat present in a food product. Therefore our invention also concerns according to a last embodiment the use of a concentrate of ursolic acid and oleanoic acid or its salts with the composition according to the invention wherein the concentrate is used to modify the crystallisation behaviour of a fat or a fat blend in a final food product to:
(i) increase the hardness of a fat blend or the final product and/or
(ii) to improve the plasticity of the fat blend or final product and/or
(iii) to improve the oral mouthfeel of the fat blend or the final product and/or
(iv) to improve the heat resistance of the fat blend or the final product and/or
(v) to improve the speed of crystallisation of the fat blend or the final product and/or
(vi) to increase the aeration properties of the fat blend or the final product and/or
(vii) to decrease drying times of ice cream coatings